Amylyx to withdraw ALS drug from market

April 4, 2024

Amylyx Pharmaceuticals is discontinuing its ALS treatment, Relyvrio, after phase 3 trial results failed to demonstrate the drug’s efficacy.

Just last month, the drugmaker shared disappointing results from a confirmatory study on Relyvrio, which failed to meet primary or secondary goals. The phase 3 PHOENIX trial, involving 664 adults with ALS, did not achieve statistical significance in changing the revised ALS functional rating scale after 48 weeks.

Relyvrio's approval in 2022 followed a notable reversal by an FDA advisory committee, which endorsed the drug on its second review. The medication, combining sodium phenylbutyrate and taurursodiol, is designed to protect neurons by blocking pathways that cause cell death, and it can be used alone or with other treatments. Previous studies had shown Relyvrio could slow physical decline in ALS patients, representing a breakthrough in treating this neurodegenerative condition.

But this week, the company announced that it will stop offering the treatment to new patients immediately and will allow existing patients to continue receiving the drug for free.

In a way, the writing has been on the wall all along. Despite securing approval, Relyvrio's regulatory journey was fraught with challenges even after receiving its nod from the agency. In February of last year, health insurance giant Cigna decided not to cover the drug, calling it “experimental, investigational and unproven.” Adding insult to injury, a few months later Relyvrio faced rejection (for the second time) by the European Union's medicines regulator.

To pile on the bad news, Amylyx also revealed its plans to reduce its workforce by 70% to allocate resources towards its main clinical and preclinical programs, aiming to extend its cash runway into 2026. These programs include ongoing research into AMX0035 for Wolfram syndrome and progressive supranuclear palsy (PSP), as well as AMX0114 for ALS.

Despite the withdrawal of Relyvrio, Amylyx hopes to focus on treatments that target endoplasmic reticulum stress and mitochondrial dysfunction.